JP2003518344A - Method and apparatus for controlling transmission in a gated communication system - Google Patents

Abstract

(57) Abstract: A method and apparatus for controlling transmission in a gated communication system. A method and system for communicating frames of information according to a discontinuous transmission format. With transmission scaling and energy scaling that simultaneously reduces the battery usage of the variable rate wireless communication device (50), increases the capacity of the reverse link, and provides reliable communication of 1 / 8th rate frames, This is a method of transmitting a 1 / 1-rate voice or data frame. To achieve this goal, four methods are shown for the transmission of eighth rate data frames, where half of the frames are gated out and the remaining data is transmitted at normal transmit energy. In addition, the power control system checks the forward link power control bits gated out by the remote station (50) and suspends the adjustment of the transmit energy according to the check result.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD OF THE INVENTION

The present invention relates to communications. More specifically, the present invention relates to new and improved methods and apparatus for transmitting variable rate data in a wireless communication system.

[0002]

[Prior art]

The use of code division multiple access (CDMA) modulation is one of several approaches to facilitate communication with many system subscribers. In this industry,
Other multiple access communication system techniques are known, such as time division multiple access (TDMA) and frequency division multiple access (FDMA). However, CDMA spread spectrum modulation techniques have many advantages over these modulation techniques for multiple access communication systems. The use of CDMA techniques in multiple access communication systems is entitled "Spread Spectrum Multiple Access Communication Systems Using Satellite or Earth Repeaters",
It is disclosed in US Pat. No. 4,901,307, assigned to the assignee of the present invention and incorporated herein by reference. The use of CDMA techniques in multiple access communication systems is further assigned to the assignee of the present invention and entitled "Systems and Methods for Signal Waveform Generation in CDMA Cellular Telephone Systems," incorporated herein by reference. , U.S. Pat. No. 5,103,459.

Due to its inherent property of being a wideband signal, CDMA provides a form of frequency diversity by spreading the signal energy over a wide band. As a result, frequency selective fading affects only a small portion of the CDMA signal bandwidth. Spatial or path diversity is provided by providing multiple signal paths from one mobile subscriber through two or more cell sites, simultaneously existing links. In addition, path diversity, through spread spectrum processing, allows the signals arriving with different propagation delays to be received and processed separately.
It may be obtained by using a multipath environment. Examples of path diversity, both of which are assigned to the assignee of the present invention and incorporated herein by reference, entitled "Methods and Systems for Providing Soft Handoff of Communications in CDMA Cellular Telephone Systems," United States of America. No. 5,101,501 and US Pat. No. 5,109,390 entitled "Diversity Receiver in CDMA Cellular Telephone System".

A method for voice transmission in a digital communication system that offers the special advantage of increasing capacity while maintaining a high quality of perceived voice is
It relies on the use of variable rate speech coding. A particularly useful method and apparatus for a variable rate speech coder, entitled "Variable Rate Vocoder," is assigned to the assignee of the present invention and is incorporated herein by reference, US Pat. No. 5,414,79.
6 in detail.

The use of a variable rate speech encoder provides for data frames of maximum speech data capacity when the speech encoder is providing speech data at the maximum rate. When the variable rate speech coder is providing speech data below the maximum rate, there is extra capacity in the transmitted frames. Has a fixed preset size,
And a method for transmitting additional data in a transmission frame in which the data source for the data frame is providing the data at a variable rate is described in "Method and apparatus for formatting data for transmission. US Patent No. 5, assigned to the assignee of the present invention and incorporated herein by reference.
, 504, 773. In the patent applications mentioned above, methods and apparatus are disclosed for combining different types of data from different sources in a data frame for transmission.

In frames that contain less than a preset capacity of data, power consumption may be reduced by gating the transmission with a transmit amplifier such that only the portion of the frame that contains the data is transmitted. Moreover, message collisions within the communication system may be reduced if the data is placed in frames according to a preset pseudo-random process. Methods and apparatus for gating transmissions and locating data within frames are assigned to the assignee of the present invention, entitled "Data Burst Randomizer," and incorporated herein by reference. U.S. Pat. No. 5,659,569.

A useful method for mobile power control in a communication system is at a base station,
Monitoring the power of the received signal from the wireless communication device. Depending on the monitored power level, the base station sends power control bits to the wireless communication device at regular intervals. A method and apparatus for controlling transmit power in this manner is assigned to the assignee of the present invention, entitled "Method and Apparatus for Transmit Power Control in a CDMA Cellular Mobile Phone System," and incorporated herein by reference. No. 5,056,109, incorporated herein by reference.

In communication systems that provide data using the QPSK modulation format, the vector product of the I and Q components of the QPSK signal provides very useful information. By knowing the relative phase of the two components, the speed of the wireless communication device relative to the base station can be approximately determined. A description of a circuit for determining the vector product of I and Q components in a QPSK modulated communication system is assigned to the assignee of the present invention, entitled "Pilot Carrier Dot Product Circuit," and incorporated herein by reference. US Pat. No. 5,506,865
Is disclosed in.

There is an ever-increasing demand for wireless communication systems to enable transmission of digital information at high rates. One method for transmitting high rate digital data from a wireless communication device to a central base station is to allow the wireless communication device to send data using the spread spectrum technique of CDMA. One method that has been proposed is to allow the wireless communication device to transmit that information using a combination of small orthogonal channels. Such a method is co-pending US patent application Ser. No. 08/886, entitled "High Data Rate CDMA Wireless Communication System," assigned to the assignee of the present invention and incorporated herein by reference. Details are described in 604.

In the application just described, a pilot signal is transmitted on the reverse link (link from the wireless communication device to the base station) to enable continuous demodulation of the reverse link signal at the base station. System is disclosed. Using this pilot signal data, the base station determines the phase offset of the reverse link signal,
By removing it, a series of processes can be performed. The pilot data can also be used to properly weight the multipath signals received with different time delays before they are combined at the Rake receiver. Once the phase offset is removed and the multipath signals are correctly weighted, they can be combined to reduce the reverse link signal power that needs to be received for correct processing. it can. This reduction in required received power allows higher transmission rates to be successfully handled, or conversely, reduces interference between the reverse link signal combinations.

While some additional transmit power is required for the transmission of pilot signals,
At higher transmission rates, the ratio of pilot signal power to total reverse link signal power is substantially lower than that of the lower data rate digital voice data transmission cellular system combined. Thus, in a high data rate CDMA system, the Eb / N0 gain achieved by using a series of reverse links outweighs the additional power required to transmit pilot data from each wireless communication device. .

However, if the data rate is relatively low, the continuously transmitted pilot signal on the reverse link will contain more energy than the data signal.
At these low rates, the benefits of continuous demodulation and reduced interference provided by the continuously transmitted reverse link pilot signal may be affected by reduced talk time and system capacity in some applications. unknown.

[0013]

[Means for Solving the Problems]

The present invention is a new and improved method and system for communicating frames of information according to a discontinuous transmission format. In particular, the present invention provides transmit gating and, at the same time, reduced battery usage of variable rate wireless communication devices, increased capacity of the reverse link, and energy for providing reliable communication of eighth rate frames. It describes a method of transmitting an eighth rate voice or data frame using scaling. In the present invention,
There, for transmission of 1/8 rate data frames, such that half of the frames are gated out, and the remaining data is transmitted at the nominal transmit energy to achieve the above mentioned goal. Two methods are shown. The features, objects and advantages of the present invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings. Like reference numerals are used throughout the drawings to identify the same.

[0014]

DETAILED DESCRIPTION OF THE INVENTION

Detailed Description of the Preferred Embodiments FIG. 1 shows a functional block diagram of an exemplary embodiment of a transmission system of the present invention embodied in a wireless communication device 50. The parties in this industry are
It will be appreciated that the method just described could be used for transmissions from a central base station (not shown) as well. It will also be appreciated that the various functional blocks shown in FIG. 1 may not be present in other embodiments of the invention. The functional block diagram of FIG. 1 is a TIA / EI, also referred to as IS-2000.
It corresponds to an embodiment useful for operation according to the A standard IS-95C. Other embodiments of the present invention are useful for other standards, including the Wideband CDMA (WCDMA) standard proposed by the standards bodies ETSI and ARIB. Reverse link modulation in the WCDMA standard and IS-9 by parties in the industry.
It will be appreciated that due to the wide range of similarities with the reverse link modulation in the 5C standard, the extension of the present invention to the WCDMA standard is easily achievable.

In the exemplary embodiment of FIG. 1, the wireless communication device comprises a plurality of discrete individual devices, identified by a short orthogonal spreading sequence, as described in US Patent Serial No. 08 / 886,604, cited above. Send the information channel of. By the wireless communication device, 5 separate code channels, namely 1) first complementary data channel 38, 2) time multiplexed channel of pilot and power control symbols 40, 3) served control channel 42, 4) The second supplemental data channel 44 and 5) the basic channel 46 are transmitted. The first supplemental data channel 38 and the second supplemental data channel 44 are digital, beyond the capacity of the base channel 46, such as for facsimile, multimedia applications, video, e-mail messages, or other forms of digital data. Communicate data. The multiplexed channel of pilot and power control symbols 40 controls the pilot symbols that enable continuous demodulation of the data channel by the base station and the transmit energy of the base station or the base station in communication with the wireless communication device 50. Carry power control bit for. The control channel 42 conveys control information for the base station, such as the mode of operation of the wireless communication device 50, the capabilities of the wireless communication device 50, and other necessary signaling information. The basic channel 46 is a channel used for transmitting original information from the wireless communication device to the base station.
For voice transmission, the base channel 46 carries voice data.

Supplemental data channels 38 and 44 are encoded, processed, and provided to modulator 26 for transmission by means not shown here. The power control bits are provided to an iterative generator 22 which provides a repeat of the power control bits before providing the bits to a multiplexer (MUX) 24. In the multiplexer 24, the redundant power control bits are time multiplexed with the pilot symbols and the modulator 26
Given on line 40 to.

The message generator 12 generates the required control information message and provides this control message to the CRC and tail bit generator 14. The CRC and tail bit generator 14 adds a series of cyclic redundancy check bits, which are parity bits used to check the accuracy of the decoding at the base station, for the decoder of the base station receiver subsystem. A preset series of tail bits is added to the control message to clear the memory. The message is then provided to encoder 16 which provides forward error correction coding over the control message. The encoded symbols are provided to an iterative generator 20 that iterates the encoded symbols to provide additional time diversity during transmission. According to the iterative generator, the exact symbols follow a certain preset puncturing pattern to give a preset number of symbols in the frame, the puncturing element (PUNC).
) 19 punctures. This symbol is then provided to an interleaver 18, which sorts the symbol according to a preset interleaving format. The interleaved symbols are provided on line 42 to modulator 26.

The variable rate data source 1 generates variable rate data. In the exemplary embodiment, variable rate data source 1 is the variable rate speech encoder described in the aforementioned US Pat. No. 5,414,796. Variable rate speech encoders are common in wireless communications because their use increases battery life in wireless communication devices and increases system capacity while minimizing their impact on perceived voice quality. is there. The Telecommunications Machinery Manufacturers' Association has compiled this most popular variable rate speech encoder into standards such as Interim Standard IS-96 and Interim Standard IS-733. These variable rate speech encoders encode speech signals according to the level of speech activity into four possible rates, referred to as full rate, half rate, quarter rate, or eighth rate. Rate indicates the number of bits used to encode a frame of speech and varies on a frame-by-frame basis. Full rate uses a preset maximum number of bits to encode the frame, half rate uses half of the preset maximum number of bits to encode the frame,
The quarter rate uses one-fourth of the preset maximum number of bits to encode the frame, and the one-eighth rate uses the preset maximum number of bits to encode the frame. Use one eighth of the number.

The variable rate data source 1 provides encoded voice frames to the CRC and tail bit generator 2. The CRC and tail bit generator 2 adds a series of cyclic redundancy check bits, which are parity bits used to check the decoding accuracy at the base station, and clears the decoder memory at the base station. In order to do so, a series of preset tail bits is added to the control message. The frame is then provided to encoder 4 which provides a forward error correction code on the speech frame. The encoded symbols are provided to an iterative generator 8 which provides an iteration of the encoded symbols. According to the iterative generator, the exact symbols are punctured by the puncturing element 9 according to a preset puncturing pattern to give a preset number of symbols in the frame. The symbols are then provided to an interleaver 6 which rearranges the symbols according to a preset interleaving format. The interleaved symbols are provided on line 46 to modulator 26.

In the exemplary embodiment, modulator 26 modulates the data channel according to a code division multiple access modulation format and provides the modulated information to transmitter (TMTR) 28. The transmitter then amplifies and filters the signal and provides this signal through the duplexer 30 for transmission through the antenna 32.

In the exemplary embodiment, variable rate data source 1 sends a signal to control processor 36 that indicates the rate of the encoded frame. According to the rate instruction,
The control processor 36 provides the transmitter 28 with a control signal indicating transmission energy.

In IS-95 and cdma2000 systems, a 20 ms frame is divided into 16 sets of equal numbers of symbols, referred to as power control groups. The query for power control is that for each power control group, the base station receiving the frame issues a power control command in response to the determination of the sufficiency of the reverse link signal received at the base station. It is based on the actual situation.

FIGS. 3-5 illustrate transmit energy versus time (within a power control group) for three transmit rates—full, half, and quarter. In addition, Figures 3-9 show that eighth rate frames (eighth rat
4 separate selectable embodiments for transmission in e frame) are described. Since much redundancy is introduced in frames smaller than full rate, the energy with which a symbol is transmitted may be reduced approximately proportionally to the amount of additional redundancy in the frame.

[0024]   In FIG. 3 for full rate frame 300, each power control group PCG _{From 0} PCG₁₅Is transmitted with energy E. For simplicity, the frame is
It is described as being transmitted with equal energy for the duration of the frame. This
Parties in the industry say that energy will change over the frame,
And what is shown in Figures 3-9 is where the frame will be transmitted.
Understand what is considered as baseline energy, with no external influence.
Let's do it. In the exemplary embodiment, remote station 50 originates from and internally at the base station.
Closed loop power control command and based on the received forward link signal.
Respond to the power control command. The response to the power control algorithm is the transmitted energy
Will cause the frame to change for the duration of the frame.

In FIG. 4 for half-rate frame 302, the energy is equal to half the preset maximum level, or E / 2. This is shown in FIG. The interleaver structure spreads the repeated symbols over the frame for maximum time diversity.

In FIG. 5 for quarter rate transmission 304, frames are transmitted at about one quarter of a preset maximum level, or E / 4.

In an exemplary embodiment, the pilot signal is transmitted continuously during the transmission of full rate, half rate and quarter rate frames. However, in FIGS. 6-9, transmitter 28 gates the transmission of half a frame. In selected embodiments, the pilot channel is also gated off to reduce battery consumption and increase reverse link capacity during periods when the traffic channel transmission is gated off. In each of the embodiments, the frame is transmitted at 50% duty cycle with the transmit energy gated off for half the time. During the time a frame is being transmitted, the energy is approximately measured as the E / 4 energy at which a quarter frame is transmitted. However, through extensive simulations, the inventor has found that for selectable embodiments for transmitting 1/8 rate frames, a selected average or criterion at which 1/8 frames should be transmitted. The line energy is determined. These energies are
It is calculated to maximize battery savings and reverse link capacity while maintaining a level of reliability for transmission.

In the first embodiment shown in FIG. 6, frames are transmitted such that they are gated off alternately at 1.25 msec intervals. Therefore, the transmitter 28
It is first gated off during the first 1.25 ms. The second power control group (PCG1) is then transmitted with energy E1 for the second 1.25 ms. The third power control group (PCG2) is gated off. In this example, all odd power control groups (1,3,5,7,9,11,1)
3,15) are all even power control groups (0,2,4,6,8,10,1).
2, 14) is transmitted while gated off. This puncturing structure discards half of the repeated symbols, giving approximately four variants for each transmitted symbol. In the first embodiment chosen, the symbols are transmitted at an average or baseline energy of 0.385E. In the selected embodiment,
Gating of the transmitter 28 is performed so that the last part of the frame is not gated off. This method was chosen because it allows meaningful closing power control commands to be sent by the receiving base station to aid in the reliable transmission of the next frame.

A selected embodiment of the present invention, the second embodiment of which is shown in FIG.
The frames are transmitted such that they are gated off alternately at 2.5 millisecond intervals.
The transmission method shown in FIG. 7 represents an embodiment chosen because this results in optimal battery savings and reverse link capacity. First 2.5 ms interval (PC
During G0 and PCG1), transmitter 28 gates off. The transmitter 28 then gates on for the next 2.5 milliseconds (PCG2 and PCG3), and so on. In this example, the power control groups 2, 3, 6, 7, 10,
Gates 11, 14 and 15 are turned on, while gates 0, 1, 4, 5, 8, 9, 12, and 13 are turned off. This puncturing structure is designed to discard exactly half of the repeated symbols during the gate-off period in this embodiment. In the second embodiment chosen, the symbols are transmitted with an average or baseline energy of 0.32E.

In the third embodiment shown in FIG. 8, frames are transmitted in such a manner that they are gated off at intervals of 5.0 milliseconds. The first 5.0 ms interval (PCG0-
During PCG3), transmitter 28 gates off. Then, at the next 5.0 millisecond interval, the power control groups 4, 5, 6, 7 are transmitted and so on. In this example, the power control groups 4,5,6,7,12,13,14,1
5 is transmitted, while the power control groups 0, 1, 2, 3, 8, 9, 10, 11 are gated off. The puncturing structure is designed to discard exactly half of the repeated symbols during the gate-off period in this embodiment. In the third embodiment chosen, the symbols are transmitted with an average or baseline energy of 0.32E.

In the fourth embodiment shown in FIG. 9, the frame is transmitted to be gated off during the first 10 ms. In the next 10 ms interval, power control groups 8 to 15 are transmitted. In this embodiment, the power control groups 8, 9, 10, 11, 12, 13, 14, 15 are transmitted, while the power control groups 0, 1, 2, 3, 4, 5, 6, 7 are gated off. It This interleaver structure discards exactly half of the repeated symbols during the gate off in this embodiment. In the second embodiment chosen, the symbols are transmitted with an average or baseline energy of 0.335E.

FIG. 2 is a functional block diagram of an exemplary embodiment of modulator 26 in FIG. The data of the first supplemental data channel is line 3 to the spreading element 52, which covers the supplemental channel data according to a preset spreading sequence.
Given to 8. In the exemplary embodiment, the diffusing element 52 is a short Wal.
Spread the supplemental channel data with the sh sequence (++-). The spread data is provided to a relative gain element 54 that adjusts the gain of the spread complementary channel data in proportion to the energy of the pilot and power control symbols. The gain adjusted supplemental channel data is provided to a first summing input of summer 56.
The pilot and power control multiplexed symbols are provided on line 40 to the second summing input of summing element 56.

The control channel data is provided on line 42 to the spreading element 58, which covers the supplemental channel data according to a preset summing sequence.
In the exemplary embodiment, diffusion element 58 includes short Walsh sequences (
++++++++++ −−−−−−−−−−) to spread the supplemental channel data.
The spread data is provided to a relative gain element 60 that adjusts the gain of the spread control channel data in proportion to the energy of the pilot and power control symbols. The gain-adjusted control data is supplied to the third addition input of the adder 56.

Summing element 56 sums the gain adjusted control data symbols, the gain adjusted supplemental channel symbols, and the time multiplexed pilot and power control symbols and sums the first input of multiplier 72. , And to the first input of multiplier 78.

The second complementary channel is provided on line 44 to the spreading element 62, which covers the complementary channel data according to a preset spreading sequence. In the exemplary embodiment, spreading element 62 spreads the supplemental channel data with a short Walsh sequence (++-). The spread data is provided to a relative gain element 64 that adjusts the gain of the spread complementary channel data.
The gain adjusted supplemental channel data is provided to a first summing input of summer 66.

The basic channel data is provided on line 46 to the spreading element 68, which covers the basic channel data according to a preset spreading sequence. In the exemplary embodiment, spreading element 68 spreads the basic channel data in a short Walsh sequence (++++++ ------- ++++++-). The spread data is provided to a relative gain element 70, which adjusts the gain of the spread basic channel data. The gain adjusted basic channel data is
It is provided to the second adder input of adder 66.

A summing element 66 sums the gain adjusted second supplemental channel data symbol and the basic channel data symbol and sums the first input of multiplier 74 and the first input of multiplier 76. Give to input.

In an exemplary embodiment, pseudo-noise spreading using two different short PN sequences (PN _I and PN _Q ) is used to spread the data. In the exemplary embodiment, the short PN sequences, PN _I and PN _Q, are multiplied by a long PN code to provide additional privacy. Generation of pseudo-noise sequences is well known in the art and is described in detail in the aforementioned US Pat. No. 5,103,459. The long PN sequence is provided to the first inputs of multipliers 80 and 82. The short PN sequence PN _I is provided to the second input of the multiplier 80, and the short PN sequence PN _Q is provided to the second input of the multiplier 82.

The resulting PN sequence from multiplier 80 is the multipliers 72 and 7
4 to the second input of each. Resulting P from multiplier 82
The N sequences are provided to the second inputs of multipliers 76 and 78, respectively.
The product sequence from multiplier 72 is provided to the add input of subtractor 84. The product sequence from multiplier 74 is provided to the first adder input of adder 86. The product sequence from multiplier 76 is provided to the subtract input of subtractor 84. The product sequence from multiplier 78 is provided to the second add input of adder 86.

The difference sequence from subtractor 84 is provided to baseband filter 88. Baseband filter 88 performs the necessary filtering on the difference sequence and provides the filtered sequence to gain element 92. Gain element 92 adjusts the gain of the signal and provides the gain adjusted signal to upconverter 96. Upconverter 9
6 upconverts the gain adjusted signal according to the QPSK modulation format and provides the upconverted signal to a first input of adder 100.

The addition sequence from the adder 86 is given to the baseband filter 90. Baseband filter 90 performs the necessary filtering on the difference sequence and provides the filtered sequence to gain element 94. Gain element 94 adjusts the gain of the signal and provides the gain adjusted signal to upconverter 98. Upconverter 98 upconverts the gain adjusted signal according to a QPSK modulation format and provides the upconverted signal to a second input of adder 100.
The adder 100 adds two QPSK-modulated signals and outputs the result to the transmitter 2
Give to eight.

Now turning to FIG. 10, a functional block diagram of selected portions of a base station 400 according to the present invention. The reverse link radio frequency signal from the wireless communication device 50 (FIG. 1) is received by a receiver (RCVR) 402, which downconverts the received reverse link radio frequency signal to baseband frequencies. In the exemplary embodiment, receiver 402 downconverts the received signal according to a QPSK demodulation format. The baseband signal is then demodulated by demodulator 404. Demodulator 404 is further described with reference to FIG. 11 below.

The demodulated signal is provided to the accumulator 405. Accumulator 405 adds the symbol energies of the power control groups of the redundantly transmitted symbols. The accumulated symbol energy is according to a preset de-interleaving format,
It is provided to a de-interleaver 406 which rearranges the symbols. The permuted symbols decode the symbols 408 to provide an estimate of the transmitted frame.
Given to. The transmitted code estimate is then provided to a CRC check 410, which determines the accuracy of the frame estimate based on the CRC bits contained in the transmitted frame.

In the exemplary embodiment, base station 400 performs blind decoding on the reverse link signal. Blind decoding describes a method of decoding variable rate data when the receiver does not predictively know the rate of transmission. In an exemplary embodiment,
Base station 400 accumulates, de-interleaves, and decodes the data according to each possible rate assumption. The frame chosen as the best estimate is based on quality metrics such as symbol error rate, CRC checking, and Yamamoto metrics.

An estimate of the frame for each rate hypothesis is provided to control processor 414 and a set of quality metrics for each of the decoded estimates is also provided. Quality metrics may include symbol error rate, Yamamoto metrics, and CRC checking. The control processor optionally provides one of the decoded frames to the remote subscriber or declares a frame loss.

Now turning to FIG. 11, where an expanded functional block diagram for a typical single demodulation chain of demodulator 404 is shown. In the selected embodiment, demodulator 404 has one demodulation chain for each information channel. Exemplary demodulator 404 in FIG. 11 performs complex demodulation on the signal modulated by exemplary modulator 26 of FIG. As previously mentioned, the receiver (RCVR
) 402 down-converts the received reverse link radio frequency signal to baseband frequencies while generating I and Q baseband signals. Despreading modulator 502
And 504 use the long code from FIG. 1 to represent the I and Q baseband signals,
Each is subjected to despread modulation. Baseband filters (BBF) 506 and 508 are
Filter the I and Q baseband signals, respectively.

Despreading modulators 510 and 512 despread modulate the I and Q signals, respectively, using the PN _I sequence of FIG. Similarly, despreading modulators 514 and 516 respectively despread the Q and I signals using the PN _Q sequence of FIG. The outputs of despread modulators 510 and 512 are combined in combiner 518. The output of despread modulator 516 is subtracted from the output of despread modulator 512 at combiner 520.

The respective outputs of combiners 518 and 520 are then Walsh uncovered at Walsh uncoverers 522 and 524, with the Walsh code used to cover each of the channels involved in FIG. Walsh
The outputs of each of the anchors 522 and 524 are then added to one Walsh symbol by accumulators 530 and 532.

The outputs of combiners 518 and 520, respectively, are also accumulated in accumulators 526 and 52.
8 adds to one Walsh symbol. The respective outputs of accumulators 526 and 528 are then added to pilot filters 534 and 536. Pilot filters 534 and 536 generate an estimate of the channel condition by determining the estimated gain and phase of pilot signal data 40 (see FIG. 1). The output of pilot filter 534 is then output to the complex multiplier (com
in the multiplex multipliers 538 and 540, the accumulator 530
And 532 are complex multiplied by each output. Similarly, the pilot filter 53
The output of 6 is output to the accumulators 530 and 53 in the complex multipliers 542 and 544.
It is complexly multiplied by each of the two outputs. The output of complex multiplier 542 is then summed at combiner 546 with the output of complex multiplier 538. The output of complex multiplier 544 is subtracted from the output of complex multiplier 540 at combiner 548. Finally,
The outputs of combiners 546 and 548 are combined in combiner 550 to generate the associated 405 demodulated signals.

A second aspect of the invention is directed to controlling forward link transmit energy in the face of potentially gated reverse link transmissions. Forward link operation is performed when the reverse link is in the gated mode of operation. The forward link power control bits are punctured into the reverse link pilot based on whether the base station increases or decreases its transmit power. As a result, if the reverse link is gated off 50% of the time, the actual forward link power control command is sent at 400 Hz instead of 800 Hz. However, the base station does not know if the mobile station is predictively gated off. Thus, in normal operation, the base station will increase power during the interval in which the mobile station is gated off. Simulations show that if the base station does not know the mobile station's transmission mode, the base station knows that the mobile station is in gated mode and forward link power control sent to the reverse link pilot (400 Hz). It is known that there is a characteristic deterioration of about 1 dB as compared with the case of complying with a command. As a result, there would be a way for the base station to be able to detect the transmission mode (gated / ungated) of the mobile station.

One way to do this is to define a forward link power control bit loss decision region. If the dot product amplitude (sum of all combined fingers) is less than the threshold, then the erasure is determined and the forward power remains unchanged. In this way, in the gated mode, the base station will effectively respond to the 400 Hz forward link power control sent to the reverse link pilot.

As mentioned above, in the exemplary embodiment, the forward power control symbols are multiplexed into the pilot symbol stream. The demodulated pilot and power control symbols are provided to de-multiplexer 412, which separates the power control bit energy and provides the power control bit energy to control processor 414.

Control processor 414 also controls the reverse link signal provided by remote station 50.
Receive power control bit energy for other fingers. From the summed energies from the different demodulated fingers, control processor 414 generates commands to control the transmit energy of the forward link signal and provides these commands to transmitter (TMTR) 420. In the present invention, the control processor 414 detects the power control bits when the reverse link frame is gated out and compares the total energy of these bits with a threshold, if the total energy is Is less than the total threshold value, the closed-loop power control response is blocked.

Forward link traffic data for transmission to remote station 50 is provided to processing element 416, which formats and encodes the data and interleaves the resulting frames of data. The processed frame of data is provided to modulator 418. Modulator 418 modulates data for transmission on the forward link. In the exemplary embodiment, the forward link signal is CDMA.
Modulation format, and in particular according to cdma2000 or IS-2000 modulation format.

The modulated signal is provided to transmitter 420, which upconverts, amplifies, and filters the signal for transmission. The energy with which the signal is transmitted is determined according to the control signal from the control processor 414.

FIG. 12 shows the operations performed by the control processor 414. Figure 11
The uncovered pilot and power control symbols from the adders 526 and 528 at are provided to de-multiplexers 600 and 602 which separate the multiplexed power control symbol energy. The power control bit symbol energies from all fingers being demodulated are summed in finger combiner 604. The summed energy is provided to a comparator 606 which compares the summed energy with a preset threshold and outputs a signal indicating the comparison result.

If the energy of the power control bits is less than the threshold, then power control processor 608 determines that the forward link power control bits are gated out and adjusts the forward link transmit energy. To stop. If the energy of the power control bits is greater than the threshold, then power control processor 608 determines that the forward power control bits are not gated out and forwards according to the estimated value of the received power control bits. Adjust directional link transmit energy.

The preceding description of the selected embodiments is available to any party in the art.
It is provided to enable the making or use of the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art. And the general principles disclosed therein may be applied to other embodiments without the use of inventive capacity. Therefore, the present invention is not intended to be limited to the embodiments shown herein, consistent with the principles disclosed herein and novel features,
It should be the broadest match.

[Brief description of drawings]

FIG. 1 is a functional block diagram of an exemplary embodiment of a transmission system of the present invention embodied in a wireless communication device 50.

2 is a functional block diagram of an exemplary embodiment of modulator 26 of FIG.

3-9 include energy used to transmit a variable rate frame t for four different data rates, including four selectable embodiments for transmitting a eighth rate frame. Is explained.

FIG. 4 illustrates the energy used for transmission to transmit 1/8 rate frames.

FIG. 5 illustrates the energy used for transmission to transmit 1/8 rate frames.

FIG. 6 illustrates the energy used for transmission to transmit 1/8 rate frames.

FIG. 7 illustrates the energy used for transmission to transmit 1/8 rate frames.

FIG. 8 illustrates the energy used for transmission to transmit a 1/8 rate frame.

FIG. 9 illustrates the energy used for transmission to transmit a 1/8 rate frame.

FIG. 10 is a functional block diagram of selected portions of a base station 400 according to the present invention.

11 is an expanded functional block diagram of demodulator 404 in FIG. 10 for an exemplary single demodulation chain, and

FIG. 12 is a block diagram illustrating a forward link power control mechanism of the present invention.

─────────────────────────────────────────────────── ─── Continued front page    (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, I T, LU, MC, NL, PT, SE), OA (BF, BJ , CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, K E, LS, MW, MZ, SD, SL, SZ, TZ, UG , ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AG, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, BZ, C A, CH, CN, CR, CU, CZ, DE, DK, DM , DZ, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, JP, K E, KG, KP, KR, KZ, LC, LK, LR, LS , LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, MZ, NO, NZ, PL, PT, RO, R U, SD, SE, SG, SI, SK, SL, TJ, TM , TR, TT, TZ, UA, UG, UZ, VN, YU, ZA, ZW (72) Inventor Saifudin, Ahmed             California, United States             92126 San Diego, Number 128, The             Aid Coast Road 8217 (72) Inventor Tedman, Edward G. Juni             A             California, United States             92122 San Diego, Bromfield             De ave 4350 (72) Inventor Butler, Brian Kay             California, United States             92037 San Diego, La Jola, Gu             Renwick Lane 8736 F-term (reference) 5K067 AA43 BB04 CC10 CC21 EE02                       EE10 GG08

Claims (13)

[Claims] 1. A method for transmitting, in a wireless communication device, a 1/8 rate frame of information, wherein one frame is divided into 16 frame intervals of equal duration containing an equal number of symbols, the method comprising: A method comprising the steps of (a) gate off transmission during a first frame interval, and (b) transmit at the next frame interval: 2. The method of claim 1, wherein the pattern resulting from the transmitting steps (a) and (b) is repeated seven consecutive times. 3. The method of claim 1, wherein a 1/8 rate frame is transmitted at a baseline energy of approximately 38.5% of the preselected transmission energy for maximum rate transmission. 4. A method for transmitting a 1/8 rate frame of information in a wireless communication device, wherein one frame is divided into 16 frame intervals of equal duration containing an equal number of symbols. , (A) gate off transmission during the first and second frame interval periods, and (b) transmit symbols during the third and fourth frame interval periods. 5. The method of claim 4, wherein the pattern resulting from the transmission of steps (a)-(b) is repeated three consecutive times. 6. The method of claim 4, wherein a 1/8 rate frame is transmitted at a baseline energy that is approximately 32% of the preset transmit energy for maximum rate transmission. 7. A method for transmitting, in a wireless communication device, a 1/8 rate frame of information, wherein one frame is divided into 16 frame intervals of equal duration containing an equal number of symbols, the method comprising: (A) transmission is gated off during the first, second, third, and fourth frame intervals, and (b) fifth, sixth, seventh, and eighth. Transmitting a symbol during a frame interval of. 8. The method of claim 7, wherein the pattern of transmissions resulting from steps (a)-(b) is repeated only once in succession. 9. The method of claim 7, wherein a 1/8 rate frame is transmitted at a baseline energy that is approximately 32% of the preset transmit energy for maximum rate transmission. 10. A method for transmitting a 1/8 rate frame of information in a wireless communication device, wherein one frame is divided into 16 frame intervals of equal duration containing an equal number of symbols. , (A) gate off transmission during the first to eighth frame intervals, and (b) transmit a symbol during the ninth to sixteenth frame intervals. Method. 11. The method of claim 10, wherein a 1/8 rate frame is transmitted at a baseline energy of approximately 33.5% of the preset transmit energy for maximum rate transmission. 12. At a base station, receiving a potentially gated reverse link signal including a forward link power control bit, determining whether the power control bit is gated out, and the forward link Adjusting the forward link transmit energy according to the forward link power control bit only if the determination of whether the power control bit is gated out indicates that the power control bit is not gated out, Method for controlling transmit energy of a forward link signal. 13.   During the step of determining if the power control bit is gated out,   Measure the energy of the received power control bit, and   Compare the energy of the power control bits with a preset threshold 13. The method of claim 12 including the steps.